A dimmer switch may use one or more semiconductor switches, for example, triacs or field effect transistors (FETs) to control the amount of power delivered to a lighting load, for example, an incandescent lamp, screw-in compact fluorescent lamp (CFL), or light-emitting diode (LED) lamp. For example, the dimmer switch may control the amount of power delivered to the lighting load by controlling the phase angle P of a phase-control signal provided to the lighting load. The dimmer switch may be operable to control the phase angle P of the phase-control signal provided to the lighting load across a dimming range from a minimum phase angle PMIN (e.g., approximately 5°) to a maximum phase angle PMAX (e.g., approximately 175°), for example, in response to actuations of an intensity adjustment actuator, which may be, for example, a slider control or a rocker switch.
In a typical prior art dimmer switch, the phase angle P of the dimmer switch may be varied linearly with respect to a user-selected (or controlled) lighting intensity N, for example, as shown in FIG. 1. The controlled lighting intensity N may be varied between a minimum controlled lighting intensity NMIN and a maximum controlled lighting intensity NMAX. For example, the controlled lighting intensity N may represent the “position” of an intensity actuator (e.g., a slider control) of a dimmer switch. The relationship between the phase angle P of the phase-control signal provided to the lighting load and the controlled lighting intensity N may be referred to as a dimming curve. Some prior art dimmer switches may allow a user to linearly adjust the minimum and maximum phase angles PMIN, PMAX. When the minimum and maximum phase angles PMIN, PMAX are adjusted, the dimmer switch may linearly rescale the dimming curve between the newly-selected minimum and maximum phase angles PMIN′, PMAX′ to create an adjusted dimming curve, for example, as shown in FIG. 1. For example, a prior art dimming switch may allow for the adjustment of an initial dimming curve 110, which allows for the linear adjustment between minimum and maximum phase angles PMIN, PMAX, to an adjusted dimming curve 120, which allows for the linear adjustment between a minimum and maximum phase angles PMIN′, PMAX′. However, both the default dimming curve 100 and the adjusted dimming curve 120 provide a linear interpolation between the minimum and maximum phase angles.
However, it may be preferable to control some new load types, such as LED lamp loads, across dimming curves that are not a linear interpolation between the minimum and maximum phase angles PMIN, PMAX. Therefore, there is a need for a lighting control device that allows for user adjustment of the shape of the dimming curve in a non-linear manner.